The 1980 movie Caddyshack is a classic for its pure goofiness and laughs. But the finished film is far from what director Harold Ramis and his writing partners envisioned when they began the project. The most memorable moments of the movie were improvised, happy accidents, or workarounds. For example:

7. Bill Murray showed up for six days and made comedy history.

As a youngster, Bill Murray was a groundskeeper, a caddy, and even ran a hot dog stand at the Indian Hill Country Club, the location that inspired the Illinois setting of the film. At first, Murray's appearance as oafish groundskeeper Carl Spackler was planned as a quick cameo, but his characterization was so funny that Ramis requested he stick with the production a bit longer. Murray filmed for a total of six days, and all of his lines—including his Dalai Lama speech—were improvised on-the-spot. In fact, the only script direction for what became his "Cinderella speech" read: “Carl cuts off the tops of flowers with a grass whip.” Murray took it from there and ad-libbed lines that would, in 2005, be named to the AFI's list of greatest movie quotes of all time.

10. Caddyshack evolved into something other than “Animal House at a golf course,” and employed a classic comedy trio for inspiration.

Ramis filmed scripted scenes of Danny and the caddies running wild at the country club, believing that his scenes with Tony D’Annunzio and Maggie O'Hooligan would form the main core of the story. But viewing the dailies after a few days of shooting, Ramis realized that the scenes featuring the golfers were too essential to let go. This forced Ramis and his co-screenwriters to reconfigure the narrative focus of the coming-of-age story about Danny into a broader comedic view of the country club itself, based around the hilarious vignettes involving Murray, Dangerfield, and Chase. Ramis would now conduct Caddyshack as if it were a Marx Brothers film. According to Ramis, he thought of Dangerfield as Groucho, Murray as Harpo, and Chase as Chico.